In wireless communication systems in which portable or mobile subscriber units communicate with a base station, such as a CDMA2000 communication system, the mobile subscriber unit is typically a hand-held device, such as a cellular telephone, for example. In some embodiments, the antenna protrudes from the housing or enclosure of the mobile subscriber unit. The antenna may be a protruding monopole or dipole antenna, for example. A monopole or dipole antenna is limited to a fixed pattern, such as an omni-directional antenna pattern.
Another type of antenna used with mobile subscriber units is a switched beam antenna. A switched beam antenna system generates a plurality of antenna beams including an omni-directional antenna beam and one or more directional antenna beams. Directional antenna beams provide higher antenna gains for advantageously increasing the communications range between the base station and the mobile subscriber unit, and for also increasing network throughput. A switched beam antenna is also known as a smart antenna or an adaptive antenna array.
U.S. Pat. No. 6,876,331 discloses a smart antenna for a mobile subscriber unit. This patent is assigned to the current assignee of the present invention, and is incorporated herein by reference in its entirety. In particular, the smart antenna includes an active antenna element and a plurality of passive antenna elements protruding from the housing of the mobile subscriber unit.
Protrusion of the various types of antennas from the housing of a mobile subscriber unit may be broken or damaged when carried by a user, particularly for smart antennas. Even minor damage to a protruding antenna can significantly change its operating characteristics. In addition, lengthy protrusions take away from the appearance of mobile subscriber units.